Estimation of background carrier concentration in fully depleted GaN films

Chandrasekar, Hareesh and Singh, Manikant and Raghavan, Srinivasan and Bhat, Navakanta (2015) Estimation of background carrier concentration in fully depleted GaN films. In: SEMICONDUCTOR SCIENCE AND TECHNOLOGY, 30 (11).

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Abstract

Buffer leakage is an important parasitic loss mechanism in AlGaN/GaN high electron mobility transistors (HEMTs) and hence various methods are employed to grow semi-insulating buffer layers. Quantification of carrier concentration in such buffers using conventional capacitance based profiling techniques is challenging due to their fully depleted nature even at zero bias voltages. We provide a simple and effective model to extract carrier concentrations in fully depleted GaN films using capacitance-voltage (C-V) measurements. Extensive mercury probe C-V profiling has been performed on GaN films of differing thicknesses and doping levels in order to validate this model. Carrier concentrations as extracted from both the conventional C-V technique for partially depleted films having the same doping concentration, and Hall measurements show excellent agreement with those predicted by the proposed model thus establishing the utility of this technique. This model can be readily extended to estimate background carrier concentrations from the depletion region capacitances of HEMT structures and fully depleted films of any class of semiconductor materials.

Item Type:	Journal Article
Publication:	SEMICONDUCTOR SCIENCE AND TECHNOLOGY
Publisher:	IOP PUBLISHING LTD
Additional Information:	Copy right for this article belongs to the IOP PUBLISHING LTD, TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND
Keywords:	GaN; devices; capacitance; carrier concentration
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	30 Dec 2015 06:05
Last Modified:	30 Dec 2015 06:05
URI:	http://eprints.iisc.ac.in/id/eprint/52954

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